The present invention relates generally to printing presses and more specifically to a device for aiding placement of a printing sleeve over a cylinder of a printing press.
U.S. Pat. No. 4,089,265 purports to disclose a cylinder end fitting sleeve next to a base tube. A flexographic sleeve may be placed over the end fitting sleeve. Radial bores connect with a pressure reducing manifold to aid in sliding a flexographic sleeve onto the base tube. The end fitting sleeve can be removed once the sleeve is on the base tube.
The end fitting sleeve only contacts the flexographic sleeve at only over a limited axial extent of the flexographic sleeve and the flexographic sleeve must be fit over the end fitting sleeve while the end fitting sleeve is attached to the base tube.
U.S. Pat. No. 5,429,048, incorporated by reference herein, discloses an offset lithographic printing press including a tubular-shaped printing blanket which may be axially-removed from a blanket cylinder. The blanket has a metal inner surface, a compressible material layer and a print layer.
Such a blanket may be expandable, for example using air pressure, to aid in placement and removal of the blanket. The metal inner layer thus may be rather thin to permit this expansion, and the blanket may not be extremely rigid.
Such blankets used on such offset lithographic printing presses typically have had a circumference equal to the height of the image to be printed, i.e. a blanket size of one image. When the blanket size increases to more than one image, for example two or three images, the blanket may lack strength and compress or collapse. The roundness of the tube thus may be compromised, making placement of the tube on the blanket cylinder difficult.
U.S. Pat. No. 4,823,693 purports to disclose an auxiliary apparatus used to apply a sleeve on a cylinder. The auxiliary apparatus has a cylindrical support on which the sleeve to be applied to the cylinder is retained. The auxiliary apparatus must be rolled next to the printing press and aligned with the cylinder. The sleeve is then removed from the cylindrical support and slid over the cylinder 3.
The auxiliary apparatus of the ""693 patent is bulky and difficult to maneuver. Different height apparatuses must be supplied if the cylinders of the press with sleeves are at different heights, as the auxiliary apparatus rests on the ground. In addition a significant gap remains between the cylindrical support and the cylinder, and the placement of the large-sized sleeves with little stability on the cylindrical support is as difficult as placing the sleeve on the cylinder. Moreover, the sleeve extends axially far beyond the end of the cylindrical support. It is also difficult for a press operator to move the sleeve onto the cylinder, as the operator must stand to the side of the auxiliary device.
Commonly-owned U.S. Pat. Nos. 6,250,223 and 6,386,103 disclose blanket tube removal devices, which do not significantly increase the stability of a printing roll during placement.
An object of the present invention is to improve the stability of a printing roll when being placed on a cylindrically-shaped object.
The present invention provides a printing sleeve in combination with a support device comprising:
a printing sleeve having a first end, a second end and an interior surface; and
a support device for acting on the interior surface, the support device having a first position where the support device acts on the interior surface at both the first end and the second end, the support device aiding placement of the sleeve on a cylinder of a printing press.
The support device thus can provide stability at both ends of the printing sleeve. As the printing sleeve is being slid onto its cylinder over a cylinder end, the support device can continue to provide support directly at the cylinder end.
Preferably, the support device is attached fixedly to the device at the first end.
The support device preferably is light weight so as to be liftable by a press operator. The combination of the sleeve and the support device preferably is, for example, less than 15 kilograms.
The support device preferably includes a support cup for clearing bearings at an end of the cylinder of a press onto which the sleeve is to be placed. Thus the support device can act directly on the second end, and a space between the cylinder and the support device can be avoided.
Preferably, the support device includes an inflation device to contact the inner surface when inflated. The inflation device is easily placed inside the sleeve, even if the sleeve is unstable or flimsy. The inflation device may then be inflated to provide the desired stability.
The present invention thus also provides a printing sleeve in combination with a support device comprising:
a printing sleeve having a first end, a second end and an interior surface; and
an inflation device for acting on the interior surface of the printing sleeve when the printing sleeve is removed from a printing press.
Preferably, the inflation device includes a bellows-type support tube, and the bellows can collapse as the sleeve is pushed over its respective cylinder. The bellows may be supported by a spring support.
The inflation device may include an end part fastenable to the sleeve, and an air valve, so that as the bellows collapses, air is released and the end part remains fastened. The end part may be for example a disk made of plastic or metal. An air pressure gauge also may be provided to measure the pressure in the inflation device. An air hose can supply air through the air valve.
The end part may be fastened to the sleeve using an end ring. Opposite the end part may be the support cup for fitting over the cylinder end bearings.
The printing sleeve preferably is an offset lithographic blanket sleeve, but may be any type of printing sleeve.
The present invention also provides a method for placing a printing sleeve on a printing press comprising the steps of:
placing an inflation device inside a printing sleeve when the sleeve is removed from a printing press cylinder, and
placing the printing sleeve over the cylinder.
Preferably, the inflation device deflates during the placing step.
The present invention further provides a method for placing a printing sleeve on a printing press comprising the steps of:
placing a support device inside a printing sleeve so that the support device contacts both a first end and an opposing second end of the printing sleeve when the sleeve is removed from a printing press cylinder, and
placing the printing sleeve over the cylinder.
Preferably, the placing step includes a press operator holding both the printing sleeve and the support device.
The present invention also provides a printing sleeve in combination with a support device comprising:
a printing sleeve having a first end, a second end and an interior surface; and
a support device for acting on the interior surface, the support device and the printing sleeve being portable.
Portable as defined herein means that a press operator can lift the combination from the ground and place the combination on a cylinder.
The sleeve preferably is a printing blanket with two sets of images around the circumference.